High power semiconductor chips such as the insulated-gate bipolar transistor (IGBT) generate substantial amount of heat when in use. The typical operating temperature of an IGBT module is up to 200 Celsius, and it is designed to have a long service life of more than 10 years. With the advance in semiconductor fabrication technology, these devices are expected to shrink in size in the future. As such, it becomes an increasing challenging problem to design a compact cooling system that can dissipate the high density heat flux generated by these devices quickly and efficiently. As a result, liquid cooling is widely used in this area.
Conventional liquid cooling solutions employ an enclosed chamber that is attached to the heat generating element(s) so that when the pressurized liquid coolant passes through the chamber, it carries the heat away. The effectiveness of these cooling systems depends on a variety of factors, such as the mass flow rate of the liquid coolant, the efficiency of heat transfer from the heat generating element to the enclosed chamber and then to the liquid coolant. Over the years, many cooling systems have been developed in an attempt to improve the overall heat transfer efficiency by deploying various sub-structures inside the liquid chamber. However, the added complexity in fabricating these sub-structures may easily outweigh its gain in thermal efficiency. Another obvious solution is to employ a higher power pressurized pump to increase the fluid flow speed. But this solution will increase the overall system cost and make the overall cooling system more bulky. Therefore, a better approach is called for to circumvent above-mentioned shortcomings.